【摘要】：瀝青混合料是十分復(fù)雜的非均質(zhì)復(fù)合材料。長(zhǎng)期以來,瀝青混合料傳統(tǒng)設(shè)計(jì)體系對(duì)其宏觀性能的研究主要依賴于現(xiàn)象經(jīng)驗(yàn)法,但是其在研究過程中需要大量耗時(shí)、耗資的室內(nèi)試驗(yàn),而且得出的結(jié)果差異性大,再現(xiàn)性差,已無法滿足現(xiàn)代工程建設(shè)中高質(zhì)量的要求。瀝青混合料的宏觀性能與組分相材料性能和內(nèi)部結(jié)構(gòu)特征等密不可分,因此基于數(shù)字圖像處理技術(shù),從細(xì)觀角度研究瀝青混合料宏觀性能是十分必要的。首先,本文明確了瀝青混合料CT圖像的處理過程,提出了確定數(shù)字圖像中粗集料和空隙的閡值的同心9環(huán)狀分區(qū)方法。結(jié)表表明,采用同心9環(huán)狀分區(qū)方法提高了數(shù)字圖像中的粗集料和空隙的識(shí)別精度,特別是消除了圖像邊緣處粗集料的區(qū)域缺失,同時(shí)減少了粗集料內(nèi)部的“麻孔”現(xiàn)象。再則,本文針對(duì)兩種成型方法、多種壓實(shí)功和三種級(jí)配類型的瀝青混合料試件,基于CT技術(shù),采用沿著試件高度方向三段式(頂段、中部和底端)的分區(qū)方法對(duì)瀝青混合料內(nèi)部結(jié)構(gòu)的計(jì)算空隙率及其影響因素進(jìn)行了分析。以中部空隙率的三個(gè)特征指標(biāo)建立了混合料試件整體計(jì)算空隙率的“預(yù)測(cè)模型”,并檢驗(yàn)了“預(yù)測(cè)模型”的計(jì)算精度。根據(jù)“預(yù)測(cè)模型”和三維重構(gòu)模型分別計(jì)算得到的空隙率,分析了其與實(shí)測(cè)空隙率之間的差異。結(jié)果表明,級(jí)配類型對(duì)整體計(jì)算空隙率的有效性影響較大,成型方法和壓實(shí)功對(duì)整體計(jì)算空隙率的有效性影響較��；“預(yù)測(cè)模型”計(jì)算的結(jié)果精度較高,達(dá)到了整體計(jì)算空隙率的98.98%；與混合料實(shí)測(cè)空隙率相比,應(yīng)用“預(yù)測(cè)模型”計(jì)算AC和SMA混合料的空隙率精度較OGFC混合料的高；應(yīng)用“預(yù)測(cè)模型”計(jì)算得到的空隙率與根據(jù)三維重構(gòu)模型計(jì)算得到的差異較小。其次,為了有效的測(cè)試和評(píng)價(jià)瀝青混合料內(nèi)部結(jié)構(gòu)均勻性,考慮粗集料、瀝青砂漿和空隙各組分的作用,提出了一種以各組分密度為特征值的瀝青混合料內(nèi)部結(jié)構(gòu)均勻性識(shí)別方法(HIMDI),采用不同瀝青用量條件下三種不同級(jí)配類型的瀝青混合料試件,對(duì)其內(nèi)部結(jié)構(gòu)均勻性進(jìn)行了定量檢驗(yàn)。同時(shí),研究了瀝青用量、壓實(shí)功、級(jí)配類型對(duì)混合料試件內(nèi)部結(jié)構(gòu)均勻性的影響,以及討論了HIMDI的實(shí)際應(yīng)用。結(jié)果表明,基于本方法提出的均勻性評(píng)價(jià)參數(shù)可以識(shí)別單一或一組瀝青混合料試件的內(nèi)部結(jié)構(gòu)均勻性,并且通過分析計(jì)算得到三種不同級(jí)配類型瀝青混合料的最佳瀝青用量與室內(nèi)試驗(yàn)獲得的相差分別為0.07%、0.1%和0.55%；瀝青用量和級(jí)配類型對(duì)瀝青混合料內(nèi)部結(jié)構(gòu)均勻性具有顯著影響,而壓實(shí)功對(duì)瀝青混合料內(nèi)部結(jié)構(gòu)均勻性影響規(guī)律不同；采用均勻性評(píng)價(jià)參數(shù)識(shí)別了瀝青混合料試件的瀝青用量、均勻性的相對(duì)薄弱位置以及相同成型因素條件下試件制作的平行性。此外,基于本文提出的瀝青混合料空隙率預(yù)測(cè)模型以及均勻性評(píng)價(jià)方法,根據(jù)瀝青混合料馬歇爾設(shè)計(jì)方法中體積參數(shù)與內(nèi)部結(jié)構(gòu)組分特征值的關(guān)系,并考慮瀝青混合料內(nèi)部結(jié)構(gòu)均勻性,建立了AC和SMA混合料的最佳瀝青用量確定方法。結(jié)果表明,利用CT技術(shù)確定的混合料內(nèi)部結(jié)構(gòu)組分特征參數(shù)可以準(zhǔn)確的表征AC和SMA混合料的馬歇爾體積設(shè)計(jì)方法中的空隙率、間隙率和飽和度等體積參數(shù)；對(duì)于AC和SMA混合料,采用本文給出的瀝青混合料設(shè)計(jì)方法與根據(jù)現(xiàn)行馬歇爾設(shè)計(jì)方法分析得到的瀝青混合料最佳瀝青用量相差分別為0.01%和0.179%。
[Abstract]:Asphalt mixture is a very complex heterogeneous composite material. For a long time, the research on the macro performance of asphalt mixture based on the traditional design system mainly depends on the phenomenal experience method. However, it needs a lot of time-consuming, expensive indoor test in the study process, and the result is big difference and poor reproducibility, so it can not satisfy the modern workers. The macro performance of asphalt mixture is closely related to the properties of phase separation material and internal structure. Therefore, it is necessary to study the macro performance of asphalt mixture from the micro angle based on the digital image processing technology. First, the process of the CT image processing of the asphalt mixture is confirmed. The concentric 9 ring partition method is used to determine the gap between the coarse aggregate and the gap in the digital image. It is shown that the concentric 9 ring partition method improves the recognition accuracy of the coarse aggregate and the gap in the digital image, especially the deletion of the coarse aggregate at the edge of the image, and the reduction of the "jute hole" inside the coarse aggregate. According to two kinds of molding methods, various compaction work and three gradation types of asphalt mixture test parts, based on CT technology, the calculation of the internal structure of asphalt mixture by the method of zoning along the height direction of the specimen (top, middle and bottom) is used to analyze the calculated void ratio and the influencing factors of the internal structure of the asphalt mixture, with the three characteristics of the middle void ratio in the middle. The "prediction model" for the overall calculation of void fraction is established and the calculation accuracy of the "prediction model" is tested. According to the void ratio calculated by the prediction model and the three-dimensional reconstruction model, the difference between the calculated void ratio and the measured void ratio is analyzed. The results show that the gradation type is effective for the overall calculation of the void ratio. The effect of the molding method and the compaction work on the effectiveness of the overall calculated void ratio is smaller. The prediction model has a high accuracy and reached 98.98% of the total calculated void ratio. Compared with the measured void ratio of the mixture, the accuracy of the void ratio of the AC and SMA mixtures is calculated by using the "prediction model" than the OGFC mixture. In order to effectively test and evaluate the internal structure uniformity of the asphalt mixture, a kind of asphalt mixture with the characteristic values of each component density is proposed in order to effectively test and evaluate the internal structure uniformity of the asphalt mixture and consider the effects of the coarse aggregate, the asphalt mortar and the voidage components. The internal structure uniformity identification method (HIMDI) is used to test the internal structure uniformity of three different gradation types under different asphalt content conditions. Meanwhile, the effect of asphalt content, compaction work and gradation type on the internal structure uniformity of the mixture is studied, and the HIMDI is discussed. The results show that the uniformity evaluation parameters based on this method can identify the internal structure uniformity of a single or a group of asphalt mixture specimens, and the difference between the best asphalt content of the three different gradation types of asphalt mixture and the indoor test is 0.07%, 0.1% and 0.55% respectively. The green amount and gradation type have significant influence on the internal structure uniformity of asphalt mixture, and the influence of compaction work on the internal structure uniformity of asphalt mixture is different. Using the uniformity evaluation parameter to identify the asphalt content of asphalt mixture, the relative weak position of uniformity and the system under the same forming factors. In addition, based on the prediction model of void fraction of asphalt mixture and the method of uniformity evaluation proposed in this paper, according to the relationship between the volume parameters of the asphalt mixture Marshall design method and the characteristic value of the internal structure, and considering the internal structure uniformity of the asphalt mixture, the optimum asphalt content of the mixture of AC and SMA is established. The results show that the characteristic parameters of the internal structure of the mixture determined by CT technology can accurately characterize the volume parameters such as void ratio, clearance rate and saturation in the Marshall volume design method of AC and SMA mixture. For AC and SMA mixtures, the design method of asphalt mixture presented in this paper and the present method are based on the present method. The difference of the best asphalt content obtained by Marshall design method is 0.01% and 0.179%. respectively.
【學(xué)位授予單位】：大連海事大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：U414

【引證文獻(xiàn)】

相關(guān)會(huì)議論文 前1條

1 張倩;白燕;王天利;;瀝青混合料試件孔隙率微觀測(cè)定方法研究[A];第17屆全國(guó)結(jié)構(gòu)工程學(xué)術(shù)會(huì)議論文集（第Ⅱ冊(cè)）[C];2008年

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本文編號(hào)：2126121